A platinum catalyst and a curable organopolysiloxane composition containing said platinum catalyst.

摘要

A compsn curable at elevated temp comprises (a) an organopolysiloxane with on average at least two Si-bonded aliphatically-unsatd monovalent hydrocarbon radicals per molecule; (b) an organohydrogenpolysiloxane having at least two Si-bonded H atoms per molecule; (c) a Pt catalyst obtd by reacting a Pt halide with an organic cpd having at least one -C=-C- gp per molecule; and opt; (d) a filler. Also claimed are (i) an elastomer obtd by heating the above compsn to 50-300 deg C; (ii) a process for preparing the compsn comprising mixing (a) and (c) above, and then adding (b); and (iii) a process for preparing an elastomer by heating the compsn so prepd. (a) is pref of formula (I) R"xSiO(4-x)/2 (I); R"= (halogenated)monovalent hydrocarbon radical; and x= 1-3, at least two Si-bonded aliphatically-unsatd gps being present per molecule. (b) is pref of formula (II) R'"mSiO(4-m)/2 (II); R'"= H or R"; and m= 1-3, at least two Si-bonded H atoms being present per molecule. The Pt catalyst pref comprises 0.5-300 wt ppm (as Pt) on (a) and (b); and the compsn pref contain a filler. Filler is pref added to the compsn, esp being mixed with (a) prior to mixing with (c).